• Korean Journal of Optics and Photonics
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• v.25 no.3
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• pp.125-130
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• 2014

Holographic optical elements (HOEs) provide systems of thin-film optics that could include a variety of functions and have many advantages as optical devices in various research fields. Research and developments based on the use of HOEs in the fields of communications and displays are in progress. This paper introduces the properties of HOEs and their applications in diffractive optical elements (DOEs), holographic projection screens, and head-mounted displays (HMDs). For widespread use of HOE technology in these various applications some challenges need to be solved, as discussed in this paper.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.489-489
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• 2013

AF 코팅은 유리나 플라스틱과 같은 기재 표면을 특수 처리하여 지문과 같은 오염물질의 부착방지와 오염물질이 부착되더라도 쉽게 제거 가능하도록 하는 기술이다. 전자, 자동차, 건축, 섬유, 철강분야 등에 활용 가능한 중요기술로 박막의 발수 발유 기능을 부여하는 표면처리 기술이고, 코팅방법에는 진공증착, 스핀코팅, 딥코팅, 플로우 코팅, 스프레이 코팅 등이 있으며, 경화 방법이나 접촉각 등의 특성이 반영된다. 터치패널 등의 지문부착방지 기술은 불소계와 비불소계 재료로 구분할 수 있지만 지문을 쉽게 지울 수 있고, 오염 방지 기능과 내구성이 있으며, 우수한 광학특성을 유지하는 것이 과제라 할 수 있다. 그리고 항균성을 부여하는 기술도 개발되고 있다. 이런 터치패널의 강화유리에 AF 코팅한 제품은 핸드폰 글래스에 처음 적용하면서부터 실생활에 도입이 시작되고 있다. 이러한 AF 코팅을 스퍼터링 법을 이용하여 증착 시켰다. 기존에는 E-beam을 이용한 증착 방식이 주를 이루었지만, 스퍼터링 법을 이용함으로써 박막의 균일화 및 대량생산이 가능해졌다. 따라서 이 연구에서는 기존의 E-beam 방식과 sputtering 공정 중 ion source에 의한 전처리의 유무에 따른 박막의 특성을 비교하였다. 내부식성, 내마모성 시험을 거친 후, 접촉각을 측정하여 알아보았으며, 박막의 건전성 및 균일성은 FE-SEM을 이용하여 관찰하였다. 실험용 장비가 아닌 실제 생산장비인 직경 1,400 파이의 장비를 이용하여 증착하였으며 염수분무 및 내마모 시험 후, 기존 접촉각의 ${\pm}5^{\circ}$ 내외임을 확인 할 수 있었고, 박막의 건전성 또한 뛰어남을 알 수 있었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.174.1-174.1
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• 2016

무전해 도금법은 외부 전원을 인가하지 않고 환원제를 이용하여 자발적으로 금속 도금층을 형성시키는 기술로, 용액내의 환원제가 산화될 때 방출되는 전자가 금속 이온에 전이하여 금속을 코팅하는 기술이다. 그 중에서도 Cu 무전해도금은 박막 형성의 용이성 및 간단한 제조 공정으로 인한 제조 원가 절감 등의 장점으로 인해 반도체 소자 배선부분에서 건식방식으로 발생되는 한계점들에 대한 해결 기술로 주목받고 있다. 또한, 이 기술은 금속 이온이 환원제에 의해 금속으로 석출되기 때문에, 피도금물이 무전해 도금액과 균일하게 접촉하고 있으면 균일한 도금 두께를 얻을 수 있는 장점이 있어서 복잡하고 다양한 형상의 제품에 적용이 가능하다. 본 연구에서는 플라스틱, PCB 등 다양한 기판에 도금 환원제, 온도 및 시간 등 도금변수를 변경하여 Cu 도금막을 형성한 후 그 특성을 평가하였다. 도금층 두께 분석을 위해 field emission scanning electron microscope (FE-SEM), energy-dispersive spectroscopy (EDS)를 사용하였으며, 박리성 평가를 위해 cross-cutting test를 실시하였다. 실험 결과, 두께 $1{\sim}3{\mu}m$ 급의 균일한 도금층이 형성된 것을 확인하였으며, $85^{\circ}C/85%$ 고온고습 조건에서 168시간 후 박리성 평가 결과, 결함 없는 양호한 표면을 나타내었다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.1-7
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• 2010

LEDs, compared to conventional light sources, have many advantages and their applications are rapidly expanding, especially in areas such as back-lights for LCD. In this paper, we propose a new LED lamp structure suitable for applications requiring a low power. In the proposed LED lamp structures, LED chips are mounted on a transparent polycarbonate plate, and thus photons are transmitted through the both sides of the plate. The copper layer deposited on the polycarbonate plate is patterned to form circuit patten and the chip mount pad, on which LED chips are mounted. We speculate that our proposed LED lamp structures may be used as a type of plate light source.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1227-1237
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• 1988

A practically useful CAD system for mold design in the plastic injection molding processes has been developed. Even though many efforts have been tried to simulated the injection molding process, this is the first attempt toward an automatic mold design system instead of a manufacturing or a simulation system. In this system the computational routines, the data base for mold design, and the routines for three dimensional modeling are blended together so that the designed mold is obtained as a solid model. For this development, the following problems have been solved. First, the modeling capability of the plastic parts has been implemented by incorporating the modeling routines of a constructive solid geometric modeling system and developing a constant thickness modeling conditions, and that of standard mold bases have been established. Third, the experimental know-how and the empirical formulae have been collected and blended together with the modeling routines of a geometric modeling system to provide the high level commands for designing mold.

• Design & Manufacturing
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• v.10 no.2
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• pp.50-54
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• 2016

In the semiconductor industry the final products were checked for several environments before sell the products. The burning test of memory and chip was implemented in reliability for all of parts. The memory and chip were developed to high density memory and high performance chip, so circuit design was also high integrated and the test bed was needed to be thin and fine pitch socket. LGA(Land Grid Array) IC socket with thin wall thickness was designed to satisfy this requirement. The LGA IC socket plastic part was manufacture by injection molding process, it was needed accuracy, stiffness and suit resin with high flowability. In this study, injection molding process analysis was executed for 2 and 4 cavities moldings with runner, gate and sprue. The warpage analysis was also implemented for further gate removal process. Through the analyses the total deformations of the moldings were predicted within maximum 0.05mm deformation. Finally in consideration of these results, 2 and 4 cavities molds were designed and made and tested in injection molding process.

• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.163-168
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• 2009

Travel time reduction is a benefit in economic analysis. Freight transportation time reduction benefits influence the logistics industry. The objectives of this paper are to estimate the Value of Time (VOT) for transportation time reduction with logit methodology. The data of Gyeonggi-do's domestic road freight transport in 2007 are used. VOT was estimated for five commodities. An average VOT of 19,946 won/vehicle-hr was calculated; transport of electronic parts had the highest VOT. This study will help provide direction for improving Korea's road infrastructure for freight.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.1
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• pp.17-23
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• 2021

Recent studies on recyclable materials in the packaging have an increased attention due to the eco-friendly policies of reducing carbon dioxide emissions in worldwide. Roasted coffee beans mostly packed in multi-layered films and papers according to their expiration date. To satisfy both recyclability and barrier properties, researches have been continued on paper-based packaging materials to enhance their properties. In this study, packaging materials for coffee beans are developed by laminating bioplastic films on papers. The tests of packaging materials were performed with mechanical properties, gas and water vaper permeability, recyclability and storage quality for coffee beans. Compared to other samples, the paper/bioplastics-based coffee package composed of starch coated papers and two bioplastics showed the lowest barrier properties, comparable mechanical strength and ability to maintain the quality of roasted coffee beans. Thus, it could be a good alternative for multi-layered packages for roasted coffee beans.

• KDI북한경제리뷰
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• v.22 no.4
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• pp.23-38
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• 2020

본 자료에서는 1998년과 2017년의 수출유사도지수 변화를 파악함으로써 북한의 수출상품이 어떠한 소득수준의 국가와 유사한지 알아보았다. 1998년 수출유사도지수는 한국, 홍콩, 태국, 중국, 일본 순으로 높았으며 2017년에는 미얀마, 모로코, 튀니지, 방글라데시, 스리랑카 순으로 높은 것으로 나타났다. 단편적인 비교일 수 있으나, 1998년 북한의 수출 품목은 한국과 2017년에는 미얀마와 가장 유사하다고 해석 가능하다. 이어서 1998년과 2017년 북한의 수출품목의 비중변화를 관찰한 결과 광물성연료(HS 27)의 수출비중이 가장 크게 증가하였으며, 의류(HS 62), 광·슬래그·회(HS 26), 과실(HS 08), 의류(HS 61)가 뒤를 이었다. 반대로 2017년 1998년에 비해 수출비중이 가장 크게 감소한 품목으로는 전기기기(HS 85), 원자로·기계류(HS 84), 식물(HS 12), 플라스틱과 제품(HS 39), 인조스테이플 섬유(HS 55)이다. 비교분석을 위해 북한과 수출유사도지수가 가장 높은 10개 국가의 수출품목 비중 변화 역시 살펴보았는데, 자세한 품목의 비중변화는 부록의 <부표 1~10>에서 확인할 수 있다. 1998년과 2017년 각각 수출유사도지수가 가장 높았던 한국과 미얀마의 수출품목 변화는 특히 주목할 만하다. 전기기기(HS 85)의 수출이 한국에서는 가장 크게 증가한 반면, 북한에서는 가장 크게 수출이 감소한 상품이었으며, 미얀마의 경우 광물성연료(HS 27), 의류(HS 62), 광·슬래그(HS 26)의 수출이 증가한 것으로 드러난다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.200-207
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• 2016

The automotive seat is an important component that moves in sync with the driver and is actively being developed with various new functions. The aim of this work is to develop a lightweight seat cushion extension module using a lightweight material. To this end, a structural strength analysis, vertical strength test, and durability test were conducted. In the structural analysis, the maximum value of deformation under vertical load was 4.98 mm at the front of the upper panel. The maximum stress was approximately 105 MPa, which occurred at the point of contact between the upper and lower panels of the module. The vertical strength test showed a maximum vertical deformation of 5.31 mm under a vertical load, which differed from the analysis results by approximately 6.45%. The structural safety of the product was verified by the fact that it showed no harmful deformation or damage during operation after the vertical strength test and a durability test for 20,000 cycles. Furthermore, the use of engineering plastics made it possible to reduce the weight by approximately 30% compared to existing products. The lack of damage after tests verified the passenger safety, strength, and rigidity of the product. The results are expected to be applied for improving environmental and fuel efficiency regulations and preventing accidents due to driver fatigue. The applications of this module could be expanded various types of vehicles, as well as other industries in which eco-friendly and lightweight materials are used.